Do not, when clearing up the kitchen after you have cooked, take the opportunity to throw out half the useful tupperware boxes I have spent time and money collecting (the ones that fit just so in my tiny fridge), simply because you choose to bin any leftovers rather than eating them up later.
Do not spend hours spouting about how you try to only buy local organic food as it is so much better for the planet, just after binning most of my fridge's perfectly good leftovers.
Do not whinge like a small child when we put the takeaway containers in the dishwasher so they are clean for the recycling bin, and whine "Can't we just throw them away, just this once?" I'm not making you wash the sodding things up, but I'm not cluttering up my wheely bin either.
Do not ask, every single time you come to stay, which room you are sleeping in. We have a three bedroom house and two of the rooms are already occupied by permanent residents. Furthermore, when we took the time to set up the spare room for guests, we actually had a long conversation with you about the process. Work it out.
Do not pull a face when finding out that we have no intention of moving from our (perfectly pleasant modern) house ever again, because you personally cannot believe that anyone would not choose to live in a period property (complete with horrific maintenance bills and authentic draughts).
Do not try to tell me how to hang my washing on the line by describing how you learnt about it in your posh school physics lessons. I do not give a shit and frankly have more important things to worry about than the optimum way of pegging out sheets. If you do it again I will make a snarky comment about how my school (the one you look down upon because it was only a comprehensive) had a slightly more professional set of aspirations for its pupils.